Beating the $5.5 million that the Money Industry spent against Harvard Law Professor Elizabeth Warren was the easy part.

Now Warren has to decide what she’s going to do in the U.S. Senate, where just a couple of years ago, powerful pro-Wall Street Democrats like Christopher Dodd and Treasury Secretary Geithner killed any chance that she’d be confirmed to head the new Consumer Financial Protection Bureau – possibly the most significant part of the post-2008 crash financial reform legislation. As they hoped, President Obama didn’t even bother to nominate her – even though the concept of a federal agency to protect consumers against Wall Street’s misdeeds was hers.

First, Warren has to choose what role she’ll play once she’s on the inside. Its members like to think of themselves as august and deliberative, but in fact the Senate is deeply dysfunctional and its Democratic leadership easily deterred from meaningful action by the mere threat of a filibuster. In a recent New York Times piece on the Senator-elect, you could easily spot the inside-the-Beltway types trying to crush expectations – Warren’s and ours.

Don’t dismiss the perils of the decision.

Official Washington wants Warren to play the game, wait her turn, not rock the boat and eventually win the respect and support of her “colleagues” – the traditional route to power, influence and effectiveness in the Senate. Or she can damn the torpedoes and go full speed ahead in support of popular consumer reforms, at the risk of angering and alienating those who might otherwise be her allies.

And don’t forget who her true opposition is: the multinational corporations and their Washington lobbyists, who supply senators with the cash they need to get elected. That’s what drove the American economy into a depression four years ago, as we explained in our report “Sold Out: How Washington and Wall Street Betrayed America.” (PDF) Thanks to the U.S. Supreme Court’s decision in Citizens United, they’re free to spend as much of it as they want to influence the democratic process.

Senator-elect Warren has already indicated which way she’s headed. “If the notion … is we’re going to elect somebody to the United States Senate so they can be the 100th least senior person in there and be polite, and somewhere in their fourth or fifth year do some bipartisan bill that nobody cares about, don’t vote for me,” she has said.

That’s precisely the right call. Warren is a deceptively disarming warrior – I called her “the lawyer with the dragon tattoo” a few years back. She’s got unique nerd-quality credentials, a national support base, and the close attention of the news media. Not since Ralph Nader drew nationwide attention to consumer health, safety and environmental issues in the 1970s has there been such a respected and resonant voice on consumer issues.

No one else in the Senate – or even the federal government, with the exceptions of the President and the Secretary of State – comes close. She can leverage her rock star status to propel a progressive agenda of reforms that will be so popular with the public that the other 99 will have little choice but to go along. Her leadership will prove particularly helpful to her fellow Democrats, who badly need to show that as a majority they can get something done for average Americans. The Congress and the country needs a lion in the Senate. That’s what they used to call Ted Kennedy, whose seat Warren will occupy. It’s poetic politics.

The next question for Warren will be what to work on. Here are five suggestions:

1. Bankruptcy reform. Warren, a bankruptcy expert, became widely known in the 1990s for her critique of the practices of America’s banks and credit card companies in law reviews and academic pieces. When the financial industry was lobbying Congress to make it harder for the average American to declare bankruptcy, Warren penned a landmark analysis (PDF) that concluded that most Americans sought bankruptcy protection not because they were freeloaders or deadbeats but because they could no longer afford to pay their medical bills. Unfortunately, Wall Street won, and the so-called “Bankruptcy Abuse Prevention and Consumer Protection Act of 2005” made it nearly impossible for beleaguered consumers to get a fresh start – a huge victory for the credit card industry that made sure repayment of plastic debt got higher priority than child support payments, for example. Warren should investigate the inequities of the 2005 law and then seek corrective amendments.

2. Lower credit card interest rates. Having bailed out the banking industry, Congress was under pressure to do something about credit card abuses. The “Credit Card Act of 2009” was the deeply compromised and flawed result – read our analysis here.Missing, especially, was a cap on credit card interest rates. While consumers are struggling to cover their mortgages, and pay down credit card debt at 20-30% interest rates, the banks and credit card companies get to borrow taxpayer money – our money – from the Federal Reserve at nearly 0% interest rates. That needs to be fixed, and if it is: imagine the stimulus effect on the U.S. economy.

3. Fix the Senate filibuster rule. The filibuster used to be a powerful tool for a minority of members of the Senate to take on the majority: Senators could block a vote on a bill by speaking on the floor of the Senate until they dropped… or sixty Senators voted to shut down the filibuster. Unfortunately, this extraordinary measure, once rarely invoked, has devolved. Under the current practice, a Senator need only threaten a filibuster to block a vote. It’s been used hundreds of times since 2006 by Senate Republicans to derail action on important bills and judicial appointments. Warren has already pledged to revise the filibuster rule when the Senate convenes in January. As she points out, preventing abuse of the filibuster is necessary if the Senate is going to move forward to address the nation’s most pressing problems.

4. Speak out every week. Lawmaking is just one role of a U.S. Senator. Another is to use the power and influence of the position to investigate and highlight problems in and outside of government. Wisconsin Senator William Proxmire did just that in the 1970s and 1980s through what he called “The Golden Fleece Award,” which he presented monthly to public officials who, he believed, were wasting taxpayer money. Proxmire’s pronouncements, which both amused and maddened taxpayers, were closely followed by the news media. Warren should initiate a weekly tradition of calling out waste, inefficiency, and corruption, wherever it is found.

5. Restore the First Amendment to Human Beings. According to five members of the U.S. Supreme Court, the right of corporations to spend money to influence elections, and to give money and gifts to politicians for the purpose of influencing their votes, is protected by the First Amendment and cannot be limited or regulated. That’s the infamous ruling in Citizens United v. Federal Election Commission. The Supreme Court’s decision has unleashed a tidal wave of corporate money, often undisclosed, into our elections, one that has drowned out the voices of average Americans and turned our country into an aristocracy in which the People are taxed for the benefit of the powerful elites that run Wall Street and Washington. A grassroots campaign is underway to enact a Constitutional Amendment specifying that, “the protections of the First Amendment that apply to the spending of money on lobbying and elections, whether by contributions, expenditures or otherwise, shall extend only to human beings.” Senator Warren should be one of the leaders of that crucial reform.

Harvey Rosenfield has been fighting to protect consumers and taxpayers against rip-offs and abuse for thirty years. He’s the author of Proposition 103, the landmark insurance reform initiative, which has saved Californians more than $63 billion in insurance premiums.